United Drilling has assisted with numerous elevator conversions, many involving changing traction or holeless cars into holed hydraulics. All scenarios have their own unique challenges; knowing about all of the site conditions will allow us to prepare and price the project accordingly. Pricing will be based on the project specific variables: available headroom, available hoisting beam, block-out in the pit floor, capacity of the car, and the travel of the elevator.
One of the largest factors of drilling indoors is the available headroom. We require the entire shaft to be constructed prior to drilling to provide us with maximum available headroom. Why? Simply because the drill bars are added while advancing the depth of the hole and act as one single drill bar. The driller must constantly monitor plumbness which requires the tooling to be removed from the hole all at once. As an example, imagine you are drilling a 50’ hole – you would obviously need 50 feet of drill bars. If you only have 30’ of headroom you cannot pull all the drill bars out simultaneously; the limited headroom would require breaking the drill bars to remove them from the hole. This ‘breaking of the bars’ is very labor intensive…adding time to complete the job. Remember the drill bars have to be removed so we can constantly plumb the hole, guaranteeing the straightness for your new equipment. The final piece to the ‘headroom puzzle’ is that the available headroom dictates the lengths of steel casing that are being driven into the ground; the less headroom the shorter lengths of casing & the more welding; this, in turn, adds time and cost to the job.
When requesting a quote, please let us know if your elevator car is being retained or removed. If the car is being removed we are afforded the maximum available headroom which keeps the costs lower.
If the car is being removed from the hoistway we will first make sure there is a hoisting beam at the top of the shaft. If there is no hoistbeam to support 10,000 lbs then United Drilling can supply one at an added cost. If the car is remaining in the hoistway, the car must be secured at the top of the shaft and then two (2) c-channels, to support 10,000 lbs, can be through-bolted rail-to-rail to act as a hoistbeam. This can be completed by others or at an added cost by United Drilling.
SQUARE IN PIT FLOOR
Just like new construction projects it is required that the General Contractor or building owners provide a square in the pit floor in the proper location. United Drilling does give hourly rates to complete this work; however it is typically most cost effective for the GC to complete the work prior to United Drilling mobilizing.
CAPACITY AND TRAVEL OF THE ELEVATOR
The capacity and travel of the elevator dictate the depth and diameter of the quoted hole.